1. Field of the Invention
The following disclosure relates generally to an information processing apparatus, method, and program, and a storage medium storing the program for causing a computer to execute the method, each capable of enhancing the security of additional information embedded in printed material.
2. Description of the Related Art
Technologies have been and are proposed for providing added value to a printed document by embedding additional information into the printed document, that is, information that is in addition to the original contents thereof. For example, one conventional technology is known that embeds additional information in a printed document by drawing a bar code or unnoticeable pattern on the background thereof. Such additional information (hereinafter, embed information) may be, for example, the creator name of the document, the name of a person printing the document, information indicating the presence or absence of authorization to reproduce the document, and/or document print date and time.
As another conventional technology, an image processing apparatus is proposed to form an information-added image by generating a dot pattern image as embed information and adding the dot pattern image to an original image. The embed information expressed in the form of the dot pattern image includes control information regarding the authorization to reproduce the original image. Thus, the creator of the original image can control reproduction of a printed document output from the image processing apparatus. As a result, the creator may prevent the original image from being reproduced against his will.
For the above-described conventional technology, the embed information in the printed document is used to control an operation of the image processing apparatus in order to authorize or prohibit reproduction of the printed document. However, the conventional technology provides no mechanism for controlling access to and reading of the embed information. As a result, anyone having the printed document can access the embed information and thus the security thereof may be compromised.
For example, only topics for discussion in an office meeting are written on a printed document and the results of a discussion thereof may be embedded as the embed information. However, with the above-described conventional technology, anyone having the printed document can access the embed information as described above. Consequently, such confidential information as the results of the discussion might be leaked to the outside if the document is stolen or lost.